Vaillant flexoTHERM exclusive VWF 117/4 Installation And Maintenance Instructions Manual page 51

Code Meaning
F.733 Evaporation temperature too low
F.735 Evaporation temperature too high
F.740 Environment cir. inlet temperature
too low
F.741 Building circuit inlet Return tem-
perature too low
F.742 Environment cir. inlet temperature
too high
F.743 Building circuit inlet Return tem-
perature too high
0020213394_01 flexoTHERM exclusive Installation and maintenance instructions
Cause
–
No flow rate in the environment
circuit (heating mode)
–
Energy input too low in the envir-
onment circuit (heating mode) or
building circuit (cooling mode)
–
Temperature in the environment
circuit (heating mode) or building
circuit (cooling mode) too high for
compressor operation
–
Feeding of external heat into the
environment circuit
–
Inlet temperature in the environment
circuit too low for the compressor to
start for heating:
–
Air/brine: Environment circuit inlet
temperature < -28 °C
–
Ground/brine: Environment circuit
inlet temperature < -7 °C
–
Groundwater/brine: Groundwater
inlet temperature < 2 °C
–
Return temperature in the building
circuit too low for the compressor to
start
Heating:
–
Return temperature < 5 °C
Cooling:
–
Return temperature < 10 °C
–
Inlet temperature in the environment
circuit too high for the compressor to
start
–
Brine inlet temperature > 50 °C
–
Feeding of external heat into the
environment circuit
–
Return temperature in the building
circuit too high for the compressor to
start
Heating:
–
Return temperature > 55 °C to 60 °C
(depending on the brine inlet temper-
ature)
Cooling:
–
Return temperature > 35 °C
Appendix
Remedy
–
Check the flow rate in the environ-
ment circuit
–
Check the dimensioning of the en-
vironment circuit (heating mode) for
ground/brine and groundwater/brine
–
If the building circuit contains ther-
mostatic radiator valves, check that
they are suitable for cooling mode
(cooling mode)
–
VWL SA (heating mode)
–
Check the fan unit for dirt
–
Check the EEV (does the EEV
move to the limit stop? Use the
sensor/actuator test)
–
Check the low-pressure sensor and
compressor inlet sensor
–
Reduce or stop the external heat
that is entering
–
Check the de-icer (does it heat
up even though it is Off in the
sensor/actuator test?)
–
Check the EEV (does the EEV
move to the limit stop? Use the
sensor/actuator test)
–
Check the compressor inlet sensor
and low-pressure sensor
–
Check the dimensioning of the envir-
onment circuit
–
Check the sensors
–
Heating: Check that the four-way
valve functions correctly
–
Heating: Check that the four-way
valve functions correctly
–
Check the environment circuit
–
Check the sensors
–
Reduce or stop the external heat
that is entering
–
Cooling: Check that the four-way
valve functions correctly
–
Check the sensors
51